1. Field of the Invention
The present invention relates to a device for developing electrostatic latent images which uses magnetic one-component developer and eliminates density variation on the copy when developed.
2. Description of the Prior Art
In electrostatic latent image developing devices using magnetic one-component developer, a regulating member for regulating a developer layer thickness such as a doctor blade is so set that the developer layer on a carrier member for carrying a developer such as a cylindrical sleeve at the doctor blade is about 0.2 mm in thickness.
The toner as the magnetic one-component developer readily forms lumps at high temperatures and humidity and when applied with pressure. The lumps of toner are caught in the clearance between the cylindrical sleeve and the doctor blade producing longitudinal lines or density variations on the developed image. Various poroposals have been made to prevent this. As a typical example the Japanese Patent Laid-Open No. 93177/1980 is presented here which employs a magnetic blade.Although this proposal slightly reduces difficulty encountered when installing the regulating member for regulating a developer layer thickness to required accuracy, it does not solve the basic problem, that is, formation of toner lumps at the blade and longitudinal density variation resulting from it. This problem still remains with reproducing machines currently on the market which uses magnetic one-component developer.